The invention refers to a soldering head which is intended to be used in conjunction with a robot as an automatic soldering installation including at least a soldering wire dispenser, a focusing optics for a laser beam which is connected to an optical fiber, and a connecting element allowing a rigid mechanical connection of said soldering wire dispenser and said focusing optics in such a manner that the end of the soldering wire is in the area of the free, focused laser beam and is capable of being positioned in the area of a respective soldering point.
Automatic soldering installations are known. They serve to rationalize soldering techniques and operate on the basis of robots or fully automated systems. Installations are known whose soldering technique is either based on conventional soldering irons or on high-frequency soldering irons, on microflame soldering, or on induction soldering. Furthermore, installations are known where the soldering is effected by means of a controlled laser beam.
As an example of the latter case, amongst others, an installation is available where a Nd:YAG laser having an output power of 50 watts is used. The energy of this laser is conducted to the soldering point by means of a lightguide and a focusing optics. The combination of different lightguides and focusing optics allows the device to cover a wide field of applications for different soldering operations. In this known device, a diameter of the focal point between 300 and 1500 .mu.m is selected by variation of the focal length, which is about 50 to 150 mm. These different possibilities allow reaching soldering points which are difficult or impossible to reach by soldering techniques of another kind.
The advantage of laser soldering techniques is that they offer a good stability of the laser source as well as the possibility to modulate the beam in almost any manner by means of different pulse types. If the different parameters are adjusted correctly, this results in a very high quality of the soldering points and to an excellent repeatability of the soldering process. A further advantage is that the energy distribution is point-shaped and that the components are not contacted. This allows the exclusion of a large number of possible error sources and saves the workpiece, e.g. an integrated semiconductor element IC.
As an inconvenience of the described technique, it has been found that the differences in the sizes of the soldering points, which alternate randomly in the soldering sequence, are difficult to take into account in the programming of an automatic soldering installation, thereby influencing the soldering speed and the quality of the produced soldering points. It is therefore an object of the invention to improve the known laser soldering technique to eliminate the mentioned inconvenience.